1. Field of the Invention
This invention relates to the paper making and like industries including the cellulose fibre tissue industry in which the fibrous materials are converted from pulp into dry thin sheets. In paper making, particularly in producing cellulose fibre tissues the sheets usually in continuous lengths are wound onto spindles known as shells to form reels of a substantial diameter, e.g. 5 feet, and length e.g. 11 feet. The sheets are then mounted in rewinding machines in which single plies of tissue from several reels are superposed and rewound as multiple sheets on spindles sometimes known as rewind bars. Such multiple ply tissue materials in sheet form are used in such products as paper toilet rolls, handkerchiefs, table napkins, hand towels, wadding for diapers and like articles and they have the advantage that they are completely disposable as, for example in the case of toilet paper, by flushing them down a water closet. The shells comprise hollow cylinders having at their ends spindles mounted through antifriction bearings in non-rotatable supports, adapted to be removably supported in fixed bearing blocks known as gab brackets fast with respect to machine frame.
2. Description of Prior Art
In known machines for processing such materials such as the rewinding machines, a substantial amount of dust mainly of cellulose fibre base from the sheets escapes into the ambient atmosphere which creates a substantial fire hazard and creates very unfavourable conditions for the operatives supervising and servicing the machinery.
Conventionally in such rewinding machines the dust is extracted from above the sheets as they are rewound by slotted ducts close to or in contact with the surface of the sheets and being at reduced pressure the duct suction orifices collect the dust and eject it to waste. Such dust extraction means are not satisfactory, in use, particularly in modern high speed machines, since only dust in the vicinity of the suction orifices is extracted and the ambient dust laden air becomes charged with dust creating a fire hazard and hampering the machine operators. If the dust is to be removed completely a large number of ducts must be employed which take up space in the rewinding area and means have to be provided to displace these ducts to enable the wound shells to be introduced into and the empty shells to be withdrawn from the rewinding machinery. Moreover, the suction necessary at the slotted ducts to maintain the rewinding machinery substantially free of dust is of such an order that turbulence in the ambient air can cause disruption or distortion of the tissue being rewound which is moving at a high speed, e.g. 3000 to 4000 feet per minute.
In tissue rewinding machines the full shells are lowered by lifting tackle into the gab brackets in the machine frame necessitating an open topped or uninterrupted space above the machine for insertion of loaded shells and removal of empty shells. The rewound tissues are removed on their rewind bars at the take-off end of the machine by rolling them horizontally to receiving tables or like means whence they are removed for sale or to other machinery for further processing. Such machinery necessitates the retraction of some of the slotted dust extractor ducts prior to removal of empty shells and the introduction of loaded shells and the remounting of the ducts prior to rewinding creating delays which with modern high speed machinery cannot be accepted as well as increasing the initial cost and maintenance cost of the machinery. It is moreover desirable with wide loaded shells e.g. 11 feet long, to provide means for slitting the tissue ribbons longitudinally into narrower ribbons or bands as they are transferred from the shells to the rewind bars and this constitutes an area of substantial dust generation in and around the rewind machinery.
The main object of the present invention is to provide a rewind apparatus for use in rewinding paper tissue and like fibrous sheet material in which the aforesaid disadvantages are reduced or substantially eliminated.